Nonskid device



Nov. 15, 1938. Az- NN 2,137,062

NONSKID DEVICE Filed Dec. 8, 1937 I v Hermqnn R61 A MD nn INVENTOR BY WMWL a). ATTORNEY Patented Nov. 15,1938

Application December 8, 1937, Serial No. 178,683

In Switzerland December 19, 1936 1 Claim.

This invention relates to non-skid devices, particularly for horse-shoes, and also for footwear without nails and. for the travelling bands of caterpillar vehicles and the like.

It has theretofore been proposed to provide iron horse-shoes with insertions of harder material than the shoe itself, when in use the body of the.

shoe wears down quicker than the inserted fitting which in time forms a projection, i. e. a stud that extends beyond the tread proper, bears on the hard surface of the road and serves to prevent skidding. Tests have shown, however, that in spite of the material of the shoe spreading out at the inserted fittingwhich was conical outside and had its inner end cut off, the yieldingly-supported fitting readily became loose and ceased to function. On the other hand, it has been found that fittings with firm supports were subjectedto such severe wear and tear that the shoes provided with them were expensive to manufacture and not so economical as the customary cheaper shoes. For these reasons known horse-shoes with insertions of hard material have not been generally adopted in practice.

The present invention has for its main object to provide a non-skid device, particularly for horse-shoes, to which the above-mentioned de fects are not attached and which is so simple and cheap to manufacture that a shoe provided with them will be more economical than the usual shoe with steel studs.

According to the invention, a non-skid deviceof the kind described above comprises a steel support or carrier having a conical hole, and a pin of hard non-skid material having a conically tapering stem inserted in said hole so that its inner smaller end is free from the bottom of the hole and the pin is supported only by its peripheral surface.

The pin is preferably force fitted into the conical bore of its support.

When the carrier has a head into which the pin is inserted, the height of the head is preferably approximately half the diameter of its stem,

by way of example in the accompanying drawing,wherein: s

Figure 1 is a side elevation, partly in section,

to the invention, and e v Figure 2 is a like view showing a modification. Like reference characters designate 'likeparts showing one form of non-skid 'deviceac'cording W 'in both views.

Referring first to Figure 1*, the non-skid device I constitutes a horse-shoe calkin, e. g. of chromium-nickel steel, comprising acarrier I, 2 having a conical stem I and a foursided head 2. This carrier has a central longitudinal conical hole 3 extending from end to end, in which is inserted a nonskid hard-metal pin 4 of at least 9 degrees of hardness, e. g. of tungsten carbide.

The head 2 has its upper or outer end face shaped conically in order to make it as nearly as possible during the initial stages offits use, similar to the shape it will acquire owingto wear. The maximum height of the head 2 is equal to the maximum diameter of the pin, 1. e. the diameter of its upper end, or that at the bottom of the head 2. The outer end of the pin 4 is likewise raised in the middle like the adjacent end face of the head 2; as illustrated it is part-spherical, but it may be conical. This end face preferably extends beyond the top of the head a distance equal to its height, because when in use the head 2 wears more than the pin 4, so that thelatter grows, as it were, with use out of the head in any event. The pin 4 could be flush with the head 2.

In order that the pin 4 shall still be firmly held in the stem of the carrier even when the head of the'carrier has been worn down a maximum amount; the length of the pin 4 is such that it extends below the bottom face of the head 2 a distance a little greater than its diameter The pin 4 is preferably force fitted into the bore of itscarrier so that it is supported only by its peripheral surface and its end face is free. When in use, the pin is constantly pressed deeper and deeper into its carrier, the material around the pin being increasingly compressed, so that the hold of the pin in the body of the calkin constantly becomes firmer in spite of the fact that owing to wear the calkin-body constantly becomes less in height and, as use-continues, the pin extends further and further from its carrier. The non-skid effect increases with use. As the pin is pressed more firmly into its carrier when the non-skid device is in use, and as the material of the carrier at the tread surface is forced sideways, as it were, against the stem of the pin, there is no fear of the pin becoming loose or breaking until maximum admissible wear of its carrier has occurred.

The modified construction shown in Figure 2 differs from that described above with reference to Figure 1 in that the carrier stem Ia has an external screw-thread which at its upper end adjacent the head 2 merges into a non-threaded part lb which constitutes a collar so that the bottom face of the head 2 cannot bear on the horseshoe.

Instead of only one pin two or more. thereof may be inserted into a carrier, e. g. of rectangular shape as viewed in plan, common to them all.

As the pin 4 after short use extends beyond its carrier and, owing to its hardness, is subjected to no wear or to only inappreciable change of shape, the part of the ground of whatever kind and nature contacted by it is loaded specifically more heavily than by the carrier or by calkins of known kind, for which reason the pin grips the ground and has a firm hold on hard slippery surfaces, e. g. on ice-covered roads and wet asphalt.

A horse-shoe fitted with the described non-skid device is safer for Walking and standing than the usual known kind, and protects the foot-joints of animals shod with the same. The pin may consist of a hard metal or alloy and instead of being force fitted may be welded or brazed in position.

It has been found that a horse-shoe provided with such non-skid devices wears away only inappreciably or not at all, because on the hardest ground there is no sliding movement of the hoof. The. same horse-shoe can therefore be used repeatedly with several sets of the improved calkin. In consequence of the relatively shallow depth of the operative part of the herein described calkin the hoof of an animal equipped with them lies considerably nearer the ground than when it is shod with a shoe having the usual known high calkins.

Experience has shown that a horse fitted with the herein described calkin, even when the shoes become trodden down, is subjected to no injury at all or much less hurt to the crown of flesh of the hoof than with the well-known usual high calkins.

The described non-skid devices may be used in an analogous manner with footwear without nails and with the travelling treads of caterpillar vehicles and the like.

I claim:-

A calkin of the type described, comprising a steel carrier provided with a conical axial bore, and a tungsten carbide pin having a correspondingly tapered stem of a length less than that of said bore and a convex face on its wider end,v

HERMANN RAz-AMMANN. 

